Electrochemical methods, quantum chemical, and molecular dynamics methods to analyze the corrosion inhibition mechanism of phytic acid/praseodymium composite conversion coating on the AZ31B magnesium alloy

AZ31B has the advantages of high specific strength, low melting point and good toughness, but one of the significant disadvantages is poor corrosion resistance. This topic designed and prepared a corrosion-resistant composite coating of organic polymer phytic acid and rare earth praseodymium salt based on this characteristic. The test results show that the corrosion resistance of the PA/Pr composite coating is more potent than that of a single phytic acid conversion coating, and the surface of the composite layer is clustered particles with good compactness. The conversion coating mainly consists of praseodymium hydroxide, oxide and some phytate compounds. In addition, density functional theory (DFT) was used to analyze the inhibition mechanism of phytic acid; Molecular dynamics (MD) was used to evaluate the adsorption characteristics of phytic acid on metal substrates and rare earth metal oxides.